A safety cabinet has an opening portion in the front surface of a work room and a front shutter and supplies clean air to the work room from above. A side slit is provided in the side surface of the work room, air from the provided side slit joins an air flow path suctioned from a front grille of a workbench forming the bottom surface of the work room, and the turbulence of an airstream can be prevented even when a device is installed in the work room.